America’s two top defense leaders acknowledged Thursday that they’d supported a CIA plan, opposed by the White House, to arm Syrian rebels .

The notion of arming the forces trying to overthrow the government of Syrian President Bashar Assad was also backed by the State Department. But it ran counter to the view from the White House, partly out of an uncertainty about how deeply al Qaida and other anti-Western Islamist elements had infiltrated the Syrian opposition.

In fact, McClatchy reporting has revealed that much of the fighting done by the Syrian resistance has been carried about by fighters with ties to the Nusra Front, which is affiliated with al Qaida, and by many who fought for al Qaida in Iraq.

The admission came during an inquiry by the Senate Armed Services Committee into the September attack on the U.S. consulate in Benghazi, Libya. It arose when soon-to-be-retiring Secretary of Defense Leon Panetta and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, were being questioned by Sen. John McCain, R-Ariz., who seemed surprised by the answer.

McCain was wrapping up a contentious grilling of the two top Pentagon officials when he said: “And finally, I would ask, again, both of you what I asked you last March when 7,500 citizens of Syria had been killed. It’s now up to 60,000. How many more have to die before you recommend military action? And did you support the recommendation by . . . then Secretary of State (Hillary) Clinton and then head of CIA Gen. (David) Petraeus that we provide weapons to the resistance in Syria? Do you support that?”

“We do,” Panetta replied.

“You did support that?” McCain asked a second time.

“We did,” Dempsey said.

The hearing, however, was called to delve into what happened on Sept. 11, 2012, in Benghazi, when four Americans, including the U.S. ambassador to Libya, Christopher Stevens, were killed during an attack on the U.S. consulate.

Republican critics have hammered the Obama administration over the deaths, blaming its lack of response and attacking its explanations afterward. The hearing provided them an opportunity to engage in another round of finger pointing. But Panetta came prepared.

“The United States military is not and should not be a global 9-1-1 service capable of arriving on the scene within minutes to every possible contingency around the world,” he said.

The defense secretary, however, had an additional agenda for his likely final appearance before the committee – to implore lawmakers to work harder to avoid severe across-the-board budget cuts slated to take effect March 1, which he noted is already having serious impacts on military readiness.

But Benghazi was front and center.

Among the most revealing bits of information: Dempsey said that the Defense Department had not received a request for more security from the State Department in the months leading up to the attack, and that once the attack took place, military forces actually arrived as soon as was physically possible.

The most intense questioning came from Republicans, including McCain, who insisted that the military response had been inadequate because U.S. forces were at a base in Crete, which he said was only a 90-minute flight away from Benghazi.

As the questioning intensified, Panetta noted that there were 281 credible threats against U.S. installations on Sept. 11, the day of the attack. Dempsey insisted that many of them had appeared to need as much attention as those directed at Benghazi.

Sen. Kelly Ayotte, R-N.H., asked why the military did not send F-16 fighters to Benghazi in the hours after the attack.

“For a couple of reasons,” the Joint Chiefs chairman replied. “This is the middle of the night now. These are not aircraft on strip alert. They’re there as part of our commitment to NATO and Europe. And so, as we looked at the timeline, it was pretty clear that it would take up to 20 hours or so to get them there.

“Secondly, senator, importantly, it was the wrong tool for the job.”

Sen. Carl Levin, D-Mich., the chairman of the Armed Services Committee, said the emphasis should be to find the consulate attackers “and bring them to justice, and to do everything that we can to prevent it from ever happening again."

In fact, the military leaders agreed that the only appropriate security in Benghazi would have had to have come from “boots on the ground.” U.S. troops at that time were at a stage of readiness known as “N+6”, which means that from the time of notification, they had six hours to get to the aircraft and be ready to deploy. Travel time to Benghazi would have been on top of that.

Sen. Ted Cruz, R-Texas, asked: “If – and again this is a hypothetical – at 9:42 p.m. you had received a direct order to have boots on the ground to defend our men and women there, what is the absolute fastest that could have been carried out?”